JAJSNO3 January 2022 TAC5111
ADVANCE INFORMATION
The device record channel includes a high dynamic range and a built-in digital decimation filter to process the oversampled data from the multibit delta-sigma (ΔΣ) modulator to generate digital data at the same Nyquist sampling rate as the FSYNC rate. As illustrated in Figure 7-17, this decimation filter can also be used for processing the oversampled PDM stream from the digital microphone. The decimation filter can be chosen from four different types, depending on the required frequency response, group delay, power consumption, and phase linearity requirements for the target application. The selection of the decimation filter option can be done by configuring the ADC_DSP_DECI_FILT, P0_R114_D[7:6] register bits. Low power filter can be configured by setting ADC_LOW_PWR_FILT, P0_R78_D2 bit. Table 7-33 shows the configuration register setting for the decimation filter mode selection for the record channel.
P0_R78_D2 : ADC_LOW_PWR_FILT | P0_R114_D[7:6] : ADC_DSP_DECI_FILT[1:0] | DECIMATION FILTER MODE SELECTION |
---|---|---|
0 | 00 (default) | Linear phase filters are used for the decimation |
0 | 01 | Low latency filters are used for the decimation |
0 | 10 | Ultra-low latency filters are used for the decimation |
0 | 11 | Reserved (do not use this setting) |
1 | x | Low power filters are used for the decimation |